VD/VDR通过钙结合蛋白9k和28k调节胎儿骨骼发育的机制研究

骨代谢贯穿动物生命过程始终, 研究胚胎期维生素D对胎儿骨骼发育影响的机制在缺乏光照的北方高寒地区尤为重要。在前期研究中我们发现,成骨细胞中钙结合蛋白(CaBP)对维生素D呈剂量依赖，羟化酶敲除鼠股骨中CaBP 9K表达明显低于野生型，结合对孕妇及胎儿脐血的25(OH)D3的检测提示母孕期维生素D通过调节胎儿骨骼中钙结合蛋白影响胎儿骨发育。本课题将通过对北方高寒地区高危妊娠孕妇和新生儿血样标本的检测对比胎儿股骨长度，分析VD/VDR、钙结合蛋白与胎儿骨发育之间的关系。通过体内外实验明确VD/VDR及甲状旁腺素、钙、磷、甲状旁腺素对骨骼中CaBP的调控机制，利用维生素D受体及CaBP基因敲除鼠模型进行羊膜腔注射上调CaBP表达，观察给药效果，探索CaBP治疗维生素D缺乏导致骨发育异常的最佳方法和时间，为胎儿骨骼发育异常的分子靶向治疗提供新的参考。

Bone metabolism is always throughout the process of life, the vitamin D status is closely related to fetal bone mechanism in embryonic period especially in the cold region which is lack of sunshine in the north. In previous study, we observed that calcium binding protein (CaBP) in osteoblasts had a dose dependent on vitamin D. The expression of CaBP 9 k in the femur of hydroxylase null mice was significantly lower than the wild type. Considering the test of 25 (OH) D3 in pregnant women blood and paired cord blood, we speculate mother prenatal vitamin D regulates skeleton development through CaBP in fetal bones. Our research would be based on the blood samples test of high-risk pregnancy pregnant women and newborns in north cold area and fetal femur length, analyzing the relationship between VD/VDR, calbindin and fetal skeleton development. We would use northern blot,qRT-PCR, Western-blot and other methods, both in vitro and in vivo, to confirm the regulation of CaBP by VD/VDR, parathyroid hormone, calcium, phosphorus and parathyroid hormone. Furthermore we would treat vitamin D receptor and CaBP null mice with intraamniotic administration to increase the expression of CaBP to explore the best treatment strategy and timepoint of CaBP administration on treatment of vitamin D deficiency.Our study might contribute to prevention and treatment of fetal skeleton malformation.